¿ªÔÆÌåÓý

  1. Tinysa
  2. Topics

Locked Spur signals above 2.75 GHz?

 

Hi. I purchased the SeeSii TinySA Ultra+ ZS406 from Amazon last week. I'm really impressed with its design. It is a wonderful piece of hardware. I updated the firmware to the latest version, ran self test and calibration. Everything was fine...

However, when I scanned the radio frequency range from 100 kHz to 5.5 GHz with the supplied antenna, I found some suspicious patterns on the traces and waterfall. It seems that some signals above 2.75 GHz look like copies of the signals from the lower band. Are they spurious signals? Is there any way to fix it? Or is it a problem with my device? Any idea?
?
The next two screenshots below were taken during separate scans within 1.8-2.8 GHz and 4.0-5.0 GHz screen ranges:
?



The weaker signals around 2.4 GHz are from my router, I think, and the stronger yellow pattern corresponds to the 1.5 minute time interval when the microwave was on.

So it looks like false signals above 2.75 GHz to me. Does anyone have a similar problem?
 

As you are using the Ultra mode I assume you have read this page :
?
--
Designer of the tinySA
For more info go to

 

High pass filters are your friend when measuring in ultra mode.
 

John,
Can you explain for those that are less knowledgeable?
--
Designer of the tinySA
For more info go to

 

Did I read it? Oh, yes, but that was the first day I bought this device, was in a hurry to use it, and forgot about it, like about the fine print. My mistake!

After I posted my message, I did a deeper search and found your message here. Maybe I need to look for more information about TinySA Ultra+ and documentation to study how it works... But is it possible to change the IF while scanning in the GHz range? This would shift false spur and mirror signals, but leave the normally detected signals in place, right? Sorry if I'm asking something stupid, perhaps, I have to search some docs and do some research in the code on GitHub, but I would appreciate if someone gives me a hint...
 

Do any of the readers of this group remember the original Polrad spectrum analyzers?? Those were my introduction to spectrum analyzers.? When you tuned them looking for your signal, there were copious spurs moving both right and left on the screen.? How could you be sure you found what you were searching for?? Switch your apparatus off and on.? Of course, your signal mixed with the LO, so you were never sure!!??

The old HP 141's are still around with their burned CRT, variable persistence, and the BWO.? If the BWO ever went south, one had to realign the entire unit.? I'm glad those days are behind us!!

Dave - W?LEV?


On Mon, May 5, 2025 at 2:48?PM Serguei via <mirsev=[email protected]> wrote:
Did I read it? Oh, yes, but that was the first day I bought this device, was in a hurry to use it, and forgot about it, like about the fine print. My mistake!

After I posted my message, I did a deeper search and found your message here. Maybe I need to look for more information about TinySA Ultra+ and documentation to study how it works... But is it possible to change the IF while scanning in the GHz range? This would shift false spur and mirror signals, but leave the normally detected signals in place, right? Sorry if I'm asking something stupid, perhaps, I have to search some docs and do some research in the code on GitHub, but I would appreciate if someone gives me a hint...



--
Dave - W?LEV
 

On Mon, May 5, 2025 at 07:48 AM, Serguei wrote:
But is it possible to change the IF while scanning in the GHz range? This would shift false spur and mirror signals, but leave the normally detected signals in place, right?
I would welcome someone looking at the code and suggesting better ways to remove spurs and mirrors
Shifting the IF is already done.
?
--
Designer of the tinySA
For more info go to

 

I have a Polarad. Haven't used it in years. No room for it on the bench. It was my first SA

On Mon, 5 May 2025 16:56:47 +0000
"W0LEV via groups.io" <davearea51a@...> wrote:

Do any of the readers of this group remember the original Polrad spectrum
analyzers? Those were my introduction to spectrum analyzers.

--

73

-Jim
NU0C
 

I had an old HP 856/8556 BWO-based spectrum analyzer at my first job, in 1975.? It, like all of the old non-preselected analyzers, had plentiful images and mixing products.??
?
It had a Signal Identifier button which shifted the LO a certain amount; only real signals would move down and 2 scale graduations to the (?)right, others would move left or different amounts.? Built character using it to design oscillators.
73, Don N2VGU
 

I have and use an 8556 in the 852 mainframe.? Didn't know it is BWO based.? The lowest range which tops out at 3 GHz is pretty clean.? The other ranges are the problem.? And, yes, the "ID" button for use above 3 GHz which shifts legitimate signals exactly 1 MHz.? Others move much more than that.? I have other SAs, but not one that stops at 21 GHz.? Don't have the 8566, but the 8568 SA and a few others.?

Dave - W?LEV

On Tue, May 6, 2025 at 12:55?AM Donald S Brant Jr via <dsbrantjr=[email protected]> wrote:
I had an old HP 856/8556 BWO-based spectrum analyzer at my first job, in 1975.? It, like all of the old non-preselected analyzers, had plentiful images and mixing products.??
?
It had a Signal Identifier button which shifted the LO a certain amount; only real signals would move down and 2 scale graduations to the (?)right, others would move left or different amounts.? Built character using it to design oscillators.
73, Don N2VGU



--
Dave - W?LEV
 

Topic closed
--
Designer of the tinySA
For more info go to

1 - 11 of 11